You could pick up some useful clues to another site.

Items not specifically mentioned may provide much more useful clues.

But it may be possible to venture a few useful clues.

It looked like I wasn't going to find any useful clues lying around loose.

And South was left with a useful clue to the winning play.

But now she felt a spark of hope that the old woman might provide a useful clue to their search.

"We may very well find some useful clues in his calendar."

Choosing the right approach means that a character is more likely to offer useful clues.

One day, our descendants might find that a useful clue.

If it should chance they were not, he had probably found a useful clue to the thief.